Local recordings? I can suggest some things, though I'm sure someone more knowledgeable will be able to give better advice.
You can achieve lossless quality (though at a potentially MASSIVE filesize, fair warning. A one minute test video I made occupied 500mb of space.) if you disable CBR and set your CFR to 0. This may also cause some frame dropping if your computer can't handle it. If your capture is dropping frames, try to play with the CRF a bit. I've found that 10-15 provides quite clear capture without dropping any frames (for me at least). Larger numbers also = smaller filesize.
If you want to play around with it, the CPU preset setting can be used to increase the image quality without increasing the filesize, but it generally isn't worth the performance hit unless you're trying to stream good quality video over a terrible internet connection.
Also, be sure to set your YUV Color Range in advanced to "Full". I'm not sure what colour format is best, as I haven't tested that yet, but allowing OBS to use the full range of colours available is a definite must.
Furthermore, be sure to play in the same resolution you are recording at. Recording at a smaller resolution than the resolution you're playing at can cause things to be blurry/look strange.
I can provide some more tips if necessary.